I suppose the entire experience of homesickness is very individuated. It probably has a lot to do with the experiences of a place you call "home", or whether in fact there is a single place that you identify as "home" and what your connections and attachments are to it, and how much of that place is internalized in who you are. I have heard it said and I would agree, that people from cities and urban environments do not really see themselves as part of or attached to the landscape. They literally have none to attach to, other than concrete and buildings. How much of an identity is attached to that I do not personally know. There is some of course, but, whether there is the sense of rootedness like the article discusses, I do not, in my own experience, know.
I found the article to give a very good description of how I feel about being away from home. It for me has nothing to do wth the friendliness or desirability of where I am--that can be fine and well, but it still, nevertheless, is not home. The way that the article quotes Mole from Wind in the Willows and his feelings about his own home, are exactly how I feel about mine. My home, the landscape, the wide horizon and the skies, the certain warmth of a south wind in the summer, the smell of fresh hay being mown, the orange bittersweet berries in the fall, the russet of the grass in winter--those are all things with a lot of meaning to me, in a way that transcends simple landscapes...its hard to explain. I think the article does a better job than I can.